Control unit, tube unit, and micropump

ABSTRACT

A micropump including a tube unit including an elastic tube disposed in an arc shape, a plurality of fingers disposed radially from the arc shape of the tube, and a guide frame, which holds the tube and the plurality of fingers. The micropump also includes a control unit including a cam that presses the plurality of fingers, a drive section that applies torque to the cam, a control circuit that carries out a drive control of the drive section, and a machine casing that holds the cam, drive section, and control circuit. The tube unit is mountable in and removable from the control unit in a direction approximately parallel to the plane of rotation of the cam, and is mounted inside a space provided in the machine casing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/542,751 filed on Aug. 18, 2009. This application claims the benefitof Japanese Patent Application No. 2008-249798 filed Sep. 29, 2008. Thedisclosures of the above applications are incorporated herein byreference.

BACKGROUND

1. Technical Field

The present invention relates to a tube unit, a control unit, and amicropump configured with them mounted thereon.

2. Related Art

As an apparatus which transports a liquid at a low speed, there is aperistaltic drive type pump. As the peristaltic drive type pump, astructure is known in which a rotor including a plurality of rollers isrotated with a step motor as a drive source, and the rotor rotates alonga soft tube while causing the plurality of rollers to roll, carrying outa suction and discharge of a liquid (for example, Japanese Patent No.3,177,742).

This kind of pump has a configuration wherein a pump module including atube and a rotor pressing and closing the tube, and a motor moduleincluding a step motor and an output gear mechanism, are assembledstacked one on the other, a gear acting as a coupling element isprovided on the rotating shaft of the rotor, a pinion acting as a powerextraction mechanism is provided on the output gear mechanism and, whenthe pump module and motor module are connected stacked one on the other,by causing the pinion and gear to mesh with each other, a rotary driveforce of the step motor is transmitted to the rotor.

This kind of peristaltic drive type pump of Japanese Patent No.3,177,742 has a problem in that, as the tube is always pressed andclosed by the roller after the pump has been manufactured, in the eventthat there is a long period from the pump being manufactured (assembled)until it is used, the tube deteriorates, and a liquid discharge accuracycannot be secured.

Also, it is conceivable that, when the pump module and motor module aremounted stacked one on the other, as the structure causes the pinion andgear to mesh with each other, in the event that their teeth are out ofphase with each other, the pinion and gear overlap each other, and arebroken.

SUMMARY

The invention can be realized as the following embodiments orapplication examples.

Application Example 1

A micropump according to this application example includes a tube unitincluding an elastic tube, one portion of which is disposed in an arcshape, a plurality of fingers, which are disposed radially from thedirection of the radius point of the arc shape of the tube, and a guideframe, which holds the tube and the plurality of fingers; a control unitincluding a cam, which presses the plurality of fingers in order fromthe inflow side to the outflow side of the tube, a drive section, whichapplies torque to the cam, a control circuit, which carries out a drivecontrol of the drive section, and a machine casing, which holds the cam,drive section, and control circuit; a reservoir with which a flow inletof the tube communicates; and a power source which supplies electricpower to the control circuit. The tube unit is removably mounted in thecontrol unit in a direction approximately parallel to the plane ofrotation of the cam.

It is conceivable that, on the tube continuing to be in a pressed andclosed condition for a long period, the resilience of the tubedeteriorates, and a discharge accuracy decreases. However, according tothis application example, as the tube unit is separable from the controlunit including the cam which presses the plurality of fingers whichpress and close the tube, in a condition in which the tube unit isalone, the tube is maintained in an opened condition. For this reason,it is possible to prevent the decrease in discharge accuracyaccompanying the deterioration in resilience due to the continuouspressure and closure of the tube, and maintain a desired dischargeaccuracy.

Also, it is conceivable that the resilience of the tube deteriorates byrepeating the pressure and closure, and opening, of the tube for a longtime, in which kind of case a tube replacement is needed, but it ispossible to easily replace the tube as the tube unit after a certaintime of use.

Also, as the cam and drive section are configured as the control unit,when the tube unit and control unit are mounted, it is not necessarythat the kinds of pinion and gear in the previously described heretoforeknown technology are connected in mesh, meaning that there is no damagein a meshing process.

Also, in the event that the tube unit is mounted in the control unit ina direction parallel thereto, it is possible to place the plurality offingers into a condition in which they can press the tube. Consequently,no connection mechanism being needed between the motor module and pumpmodule as in the heretofore known technology, it is possible to simplifythe structure, it is possible to improve an assembling property, andfurthermore, it is possible to realize a reduction in thickness.

Also, it is possible to make the tube unit far lower in cost than thecontrol unit including the cam, drive section, and control circuit.Therein, in the event that the tube unit including the tube makingdirect contact with a chemical or the like is used once and thrown away,and the control unit is repeatedly used, it is possible to reduce arunning cost.

Application Example 2

In the micropump according to the above mentioned application example,it is preferable that the tube unit is mounted inside a space providedin the machine casing.

According to this kind of configuration, the machine casing configuringthe control unit has a casing function, eliminating a need for a casingfor housing the tube unit and control unit, enabling the simplificationin structure and the reduction in thickness.

Application Example 3

In the micropump according to the above mentioned application example,it is preferable that guide portions, which cause the radius point ofthe arc shape of the tube to approximately coincide with the rotationcenter of the cam when the tube unit is mounted in the control unit, areprovided one in each of the tube unit and the control unit.

The micropump of the above mentioned application example is configuredso that the plurality of fingers are pressed by the rotation of the cam,pressing and closing the tube. Consequently, it is necessary to causethe radius point of the arc shape of the tube to approximately coincidewith the rotation center of the cam.

Because of this, when the tube unit is mounted in the control unit, byproviding the guide portions one in each of them, it is possible tocause the radius point of the arc shape of the tube to coincide with therotation center of the cam, and all of the plurality of fingers canreliably carry out the pressure and closure of the tube withoutproviding a dedicated position regulation member.

Application Example 4

In the micropump according to the above mentioned application example,it is preferable that a detector, which detects that the radius point ofthe arc shape of the tube has coincided with the rotation center of thecam when the tube unit is mounted in the control unit, is providedbetween the tube unit and the control unit.

According to this kind of configuration, by enabling the drive of thedrive section in the event that it is detected by the detector that theradius point of the arc shape of the tube and the rotation center of thecam have been caused to coincide, the drive is carried out when in acondition in which all of the plurality of fingers have the same amountof pressure and closure, meaning that it is possible to transport theliquid at a desired flow per unit time.

Application Example 5

In the micropump according to the above mentioned application example,it is preferable that it further includes a cover member for fixing thetube unit to the control unit, and that an elastic member, which biasesthe tube unit toward the control unit in a direction in which the radiuspoint of the arc shape of the tube is caused to approximately coincidewith the rotation center of the cam, is provided between the covermember and the tube unit.

It is conceivable that, when the tube unit is fixed to the control unitusing the cover member, a horizontal space occurs between the tube unitand control unit due to a variation in dimension of component parts, andthe tube will not be able to be pressed and closed by the fingers.

Therein, by biasing the tube unit in the direction of the control unitby means of the elastic member, it is possible to bring the guideportion of the tube unit into firm abutment with the guide portion ofthe control unit, and cause the radius point of the arc shape of thetube to coincide with the rotation center of the cam, enabling each ofthe plurality of the fingers to reliably press and close the tube.

Application Example 6

In the micropump according to the above mentioned application example,it is preferable that the biasing force of the elastic member is greaterthan the pressure of the plurality of fingers against the tube.

By so doing, when the fingers press the tube, the tube unit (that is,the tube) does not move in a direction away from the fingers due to thepressure of the fingers, meaning that it is possible to reliably pressand close the tube.

Application Example 7

In the micropump according to the above mentioned application example,it is preferable that one portion, or the whole, of the machine casingand the guide frame is transparent.

By making the machine casing and guide frame transparent, it is possibleto observe the internal component parts or an engagement relationshipand drive condition of each component part. It is possible to detecttherefrom whether the condition is normal, where there is a problem, orthe like. Furthermore, it is possible to observe the amount of liquid inthe reservoir. It is sufficient that a range made transparent is a rangeof a portion desired to be observed.

Application Example 8

In the micropump according to the above mentioned application example,it is preferable that the power source is housed in the tube unit.

As the power source, in order to realize a reduction in size of themicropump, it is preferable to employ, for example, a small button typebattery or a sheet type battery.

When changing a chemical in use, or when replacing a used tube, byreplacing a battery together with the tube as the tube unit, it ispossible to prevent a battery capacity from running short during use.

Application Example 9

In the micropump according to the above mentioned application example,it is desirable that the power source is removably mounted in the tubeunit.

In the event of using a small battery as the power source, it isexpected that the battery capacity runs short during use. Therein, byadopting a configuration capable of easily replacing the battery alone,it is possible to continue to use the micropump over a long time.

Application Example 10

In the micropump according to the above mentioned application example,it is preferable that the reservoir is detachably attached to the tube.

It is conceivable that a chemical stored in the reservoir runs shortwhen the micropump is used. Therein, by adopting a configuration suchthat the reservoir is attachable to and detachable from the tube, it ispossible to remove a reservoir in which there is little chemical,connect a reservoir with a chemical stored therein to the tube, and usethe micropump over a long time.

Application Example 11

In the micropump according to the above mentioned application example,it is preferable that the reservoir is housed in the tube unit.

By so doing, in the event that the tube unit including the tube isreplaced at a point at which the liquid in the reservoir has run out, itis possible to replace the tube as the tube unit before a deteriorationof the tube considered to occur by repeating the pressure and closure,and opening, of the tube for a long time, and it is possible to increasea reliability of the micropump.

Application Example 12

In the micropump according to the above mentioned application example,it is preferable that the reservoir and the power source are housed inthe tube unit.

The tube unit is mounted in the machine casing of the control unit.Consequently, the fact that the reservoir and power source are bothprovided inside the tube unit means that they are housed in the controlunit.

This kind of configuration meaning that a substantial function necessaryfor the micropump is housed in the machine casing, as well as thereduction in size being possible, the micropump is easy to handle as ithas no parts projecting from the machine casing, and in addition, it issuitable for a case in which it is used mounted in a living organism.

Also, as it is possible to replace the battery as the tube unit inaccordance with a reservoir replacement time or a tube replacement time,it is possible to further increase the reliability.

Furthermore, in the event that the battery is provided outside themicropump, a long lead for a connection and a battery casing are neededbut, according to this application example, there is an advantage inthat they are not needed.

Application Example 13

In the micropump according to the above mentioned application example,it is desirable that the reservoir includes a port for injecting a fluidthereinto, or sealing it therein.

Herein, as the port, it is possible to employ, for example, a septum.

By providing the septum on the reservoir, it is possible to easily carryout the injection of the fluid into the reservoir in a condition inwhich the reservoir is connected to the tube.

Application Example 14

In the micropump according to the above mentioned application example,it is desirable that the reservoir is housed in the tube unit, and thatthe port is closely held to an opening provided in the guide frame, anddisposed in such a way as to expose a flow inlet of the port to theoutside of the guide frame.

According to this kind of configuration, it is possible to easily carryout an additional injection of the fluid into the reservoir in thecondition in which the tube unit is alone. Also, it is also possible toeasily carry out the additional injection of the fluid in the conditionin which the tube unit is mounted in the control unit. Furthermore, itis also possible to easily carry out the injection of the fluid in acondition in which the micropump is in use.

By closely fixing the port to the tube guide frame, it is possible toprevent an intrusion of the fluid from a space between the port and tubeguide frame into the interior of the tube unit.

Application Example 15

In the micropump according to the above mentioned application example,it is desirable that an air vent filter for blocking a passage of airbubbles is provided in a communication portion between the reservoir andthe tube.

It may happen that air merges into the fluid stored in the reservoir,and it is conceivable that the merging air gathers and turns to airbubbles as time elapses. When a liquid, is a chemical, and is dischargedinto a living organism, in the event of injecting it including airbubbles, it may happen that there occurs an effect which cannot beoverlooked.

Therein, by providing the air vent filter for allowing the liquid topass, and blocking the passage of the air bubbles, through thecommunication portion between the reservoir and tube, it is possible tosuppress the air bubbles intruding into the living organism, and it ispossible to increase safety.

Application Example 16

In the micropump according to the above mentioned application example,it is preferable that the power source is housed in the control unit.

With this kind of configuration, by housing the power source in thecontrol unit, it is possible to easily carry out the connection of thecontrol circuit and power source.

Also, by disposing the power source in a space other than a range inwhich the tube unit is mounted, it is possible to make the power sourcethicker than with the structure in which the power source is mounted inthe tube unit, meaning that it is possible to employ a battery with alarger capacity.

Furthermore, as a vacant space increases in the tube unit, it ispossible to increase the liquid capacity of the reservoir by thatamount.

Application Example 17

In the micropump according to the above mentioned application example,it is desirable that the power source is mountable in and removable fromthe control unit.

By so doing, it is also possible to replace the power source in thecondition in which the tube unit is mounted in the control unit.

Application Example 18

A control unit according to this application example, being mountable inand removable from a tube unit including an elastic tube, one portion ofwhich is disposed in an arc shape, a plurality of fingers, which aredisposed radially from the direction of the radius point of the arcshape of the tube, and a guide frame, which holds the tube and theplurality of fingers, includes a cam, which presses the plurality offingers in order from the inflow side to the outflow side of the tube; adrive section, which applies torque to the cam; a control circuit, whichcarries out a drive control of the drive section; and a machine casing,which holds the cam, the drive section, and the control circuit.

According to the configuration of this application example, the controlunit is configured including drive related components such as the drivesection, cam, and control circuit. Consequently, it is possible to carryout a drive confirmation as the control unit. Also, there being no needfor a coupling mechanism between the drive related components, it ispossible to attain a use condition immediately by slidingly mounting thetube unit.

Application Example 19

In the control unit according to the above mentioned applicationexample, it is desirable that a power source which supplies electricpower to the control circuit is removably mounted therein.

With this kind of configuration, by housing the power source in thecontrol unit, it is possible to easily carry out the connection of thecontrol circuit and power source.

Also, by so doing, it is also possible to carry out the replacement ofthe power source in a condition in which the control unit is alone, orin the condition in which the tube unit is mounted in the control unit.

Application Example 20

A tube unit according to this application example, being mountable inand removable from a control unit including a cam, a drive section,which applies torque to the cam, a control circuit, which carries out adrive control of the drive section, and a machine casing, which holdsthe cam, drive section, and control circuit, includes a tube, which isdisposed in such a way that the rotation center of the cam approximatelycoincides with the center of the arc shape of the tube; a plurality offingers, which are disposed radially from the direction of the rotationcenter of the cam; and a guide frame, which holds the tube and theplurality of fingers.

According to this application example, in the condition in which thetube unit is alone, the tube is maintained in an opened condition,meaning that it is possible to prevent a decrease in discharge accuracydue to a deterioration in resilience involved in holding the tube in apressed and closed condition.

Also, it is possible to make the tube unit far lower in cost than thecontrol unit including high cost components such as the cam, drivesection, and control circuit. Consequently, in the event that the tubeunit including the tube making direct contact with a chemical is usedonce and thrown away, it is possible to reduce the running cost.

Application Example 21

In the tube unit according to the above mentioned application example,it is preferable that the guide frame includes finger guide slotscommunicating with a tube guide groove in which the tube is inserted,and that each of the plurality of fingers includes a shaft, which isinserted in the finger guide slot, and a flange shaped tube pressingportion which, being larger than the diameter of the finger guide slot,abuts against the tube.

By so doing, in the condition in which the tube unit is alone, the tubepressing portions have a function of pressing and closing the tube, anda function of positioning an advance and withdrawal of the fingers, andit is possible to prevent the fingers from falling off the finger guideslots.

Application Example 22

In the tube unit according to the above mentioned application example,it is preferable that a reservoir communicating with a flow inlet of thetube is housed therein.

By housing the reservoir inside the tube unit, it becomes easier tohandle the tube unit including the reservoir. Also, as the reservoir andtube are connected inside the tube unit, it is possible to shorten thetube.

Application Example 23

In the tube unit according to the above mentioned application example,it is preferable that a power source which supplies electric power tothe control circuit is housed therein.

As the power source, in order to realize a reduction in size of the tubeunit, for example, a small button type battery or a thin sheet typebattery is employed.

When changing a chemical in use, or when replacing a tube used for along period, it being possible to replace a battery together with thetube as the tube unit, it is possible to prevent a battery capacity fromrunning short during use.

Application Example 24

In the tube unit according to the above mentioned application example,it is desirable that a reservoir, which communicates with the flow inletof the tube, and a power source, which supplies electric power to thecontrol circuit, are housed therein.

According to this kind of configuration, as it is possible to replacethe battery as the tube unit in accordance with the reservoirreplacement time or tube replacement time, it is possible to furtherincrease the reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic plan view showing a micropump according toEmbodiment 1.

FIG. 2 is a schematic front view showing the micropump according toEmbodiment 1.

FIGS. 3A to 3C are exploded plan views of the micropump according toEmbodiment 1.

FIGS. 4A to 4C are exploded front views of the micropump according toEmbodiment 1.

FIG. 5 is a plan view of the micropump according to Embodiment 1.

FIG. 6A is a sectional view showing the A-P-A′ section of FIG. 5, andFIG. 6B is a sectional view showing the F-F section of FIG. 6A.

FIG. 7 is a fragmentary sectional view showing a tube holding structureof the micropump according to Embodiment 1.

FIGS. 8A and 8B showing one portion of a micropump according toEmbodiment 2, FIG. 8A is a partial plan view, and FIG. 8B is a sectionalview showing the E-E section of FIG. 8A.

FIGS. 9A and 9B showing one portion of a micropump according toEmbodiment 3, FIG. 9A is a partial plan view, and FIG. 9B is a sectionalview showing the G-G section of FIG. 9A.

FIGS. 10A and 10B showing one portion of a micropump according toEmbodiment 4, FIG. 10A is a partial plan view, and FIG. 10B is asectional view showing the H-H section of FIG. 10A.

FIGS. 11A and 11B showing one portion of a micropump according toEmbodiment 5, FIG. 11A is a partial plan view, and FIG. 11B is asectional view showing the I-I section of FIG. 11A.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereafter, a description will be given, based on the drawings, ofembodiments of the invention.

FIGS. 1 to 7 show a micropump of Embodiment 1, FIGS. 8A and 8B showEmbodiment 2, FIGS. 9A and 9B Embodiment 3, FIGS. 10A and 10B Embodiment4, and FIGS. 11A and 11B Embodiment 5.

The drawings to be referred to in the following description areschematic diagrams in which the vertical and horizontal scales ofmembers and portions differ from actual ones, for the convenience ofillustration.

Embodiment 1

FIG. 1 is a schematic plan view showing the micropump according toEmbodiment 1, and FIG. 2 is a schematic front view. In FIGS. 1 and 2,the micropump 10 is integrally configured so that a tube unit 11 isslidingly inserted into a space 110 through an opening in a side surfaceof a control unit 12 on the left side as seen in the drawings, mountedin the control unit 12, and fixed to the control unit 12 with fixingscrews 90 by a fixing frame 12 acting as a cover member.

The tube unit 11 is configured of an elastic tube 50, one portion ofwhich is disposed in an arc shape, a first tube guide frame 17 andsecond tube guide frame 18 which, acting as guide frames, hold the tube50, a reservoir 14 which, having a flow inlet 52 of the tube 50communicating therewith, stores a liquid, and a plurality of fingers 40to 46. Hereafter, a description will be given, representing a fluid as aliquid such as a chemical.

The control unit 12 is configured including a cam 20, a motor andtransmission mechanism which, acting as a drive section, applies torqueto the cam 20, and a control circuit which carries out a drive controlof the motor (the illustration of the motor, transmission mechanism, andcontrol circuit is omitted).

The cam 20, motor, transmission mechanism, fingers 40 to 46, and controlcircuit are held inside a space 100 formed by a first machine casing 15and second machine casing 16 which act as machine casings.

Also, one extremity of the tube 50 being a flow outlet 53, the flowoutlet 53, passing through the fixing frame 13, and being protrudedoutward, discharges the liquid from the reservoir 14 to the exterior.

A septum 95, which acts as a port for injecting the liquid into, orsealing it in, the reservoir 14, is provided in one portion of thereservoir 14. The septum 95 is protruded inwardly of the fixing frame13.

Continuing, a description will be given of configurations of, and amethod of assembling, the tube unit 11, control unit 12, and fixingframe 13.

FIGS. 3A to 3C are exploded plan views of the micropump, and FIGS. 4A to4C are an exploded front view. In FIGS. 3A to 4C, A shows the fixingframe 13, B the tube unit 11, and C the control unit 12.

As shown in FIGS. 3A to 4C, in the control unit 12, the spaces 100 and110 are configured by the first machine casing 15 and second machinecasing 16. The cam 20, motor, transmission mechanism, and controlcircuit (the illustration of the last three is omitted) are disposed inthe space 100, and the space 110 which has an opening on one side is aspace in which the tube unit 11 is mounted.

The fingers 40 to 46 are inserted in finger guide slots 85 (providedcorresponding one to each of the fingers 40 to 46) formed by the firsttube guide frame 17 and second tube guide frame 18. Extremities on oneside of the fingers 40 to 46 are protruded in the direction of the space110, while the other extremities are protruded in a direction in whichthey abut against the tube 50 and, when the tube unit 11 is mounted inthe control unit 12, the fingers 40 to 46 attain a condition in whichthey can press and close the tube 50.

The tube 50 and reservoir 14 are connected by a communication member,and the tube unit 11, in a condition in which it is held by the firsttube guide frame 17 and second tube guide frame 18, is mounted in thespace 110 of the control unit 12 from the left side as seen in thedrawings.

The cam 20 rotates with a rotation center P as its axis. The tube unit11 is mounted in the control unit 12 so as to be parallel to the planeof rotation of the cam 20.

Also, a packing 97 is fitted along an outer peripheral surface in thefixing frame 13 side vicinity of the tube unit 11, and the space 110 ishermetically sealed in a condition in which the tube unit 11 is insertedin the control unit 12.

Also, the tube unit 11 is pushed into the control unit 12 until aconcave wall surface 18 a abuts against a wall surface 15 a of thecontrol unit 12 protruded in an arc shape. The wall surfaces 15 a and 18a are formed mutually concentric with the rotation center P of the cam20.

Herein, in a condition in which the wall surface 15 a and wall surface18 a are in abutment with each other, the dimension of the control unitside extremities 18 c and 18 d of the tube unit 11 is set in such a waythat a space is left between themselves and inner side walls 15 b and 15c of the control unit 12 (refer also to FIG. 5).

The space is provided in order to bring the wall surface 15 a and wallsurface 18 a into firm abutment, and cause a radius point P′ of an arcshaped portion (a range pressed by the fingers 40 to 46) of the tube 50to coincide with the rotation center P of the cam 20.

After the tube unit 11 is inserted into the control unit 12, the fixingframe 13 is mounted from the direction of the tail of the tube unit 11(the opening side of the space 110). Specifically, the fixing screws 90are inserted into through holes 13 d and 13 e opened in the fixing frame13, and threaded and fixed in screw holes (not shown) provided in thefirst machine casing 15 of the control unit 12.

The flow outlet 53 of the tube 50, and the septum 95 provided on thereservoir 14, being protruded from the tube unit 11, when the fixingframe 13 is fixed, the tube 50 and the septum 95 are respectivelyinserted into a tube insertion hole 13 a and a septum insertion hole 13b, and the flow outlet 53 is protruded and extended outwardly of thefixing frame 13.

A protrusion 96 is formed on a side surface of the first tube guideframe 17 on the fixing frame 13 side. The protrusion 96 is used whenremoving the tube unit 11 from the control unit 12. The protrusion 96 ishoused inside a recess 13 c bored in the fixing frame 13.

Continuing, a description will be given, referring to the drawings, of aconfiguration and operation of each component of the micropump 10assembled in the way heretofore described.

FIGS. 5 to 7 showing the micropump according to the embodiment, FIG. 5is a plan view, FIG. 6A a sectional view showing the A-P-A′ section ofFIG. 5, FIG. 6B a sectional view showing the F-F section of FIG. 6A, andFIG. 7 a fragmentary sectional view showing a tube holding structure.Firstly, a description will be given, referring to FIGS. 5 and 6, of aconfiguration of the drive section. FIG. 5 represents the second machinecasing 16 and second tube guide frame 18 in perspective.

The drive section, including a step motor 70 as the motor, transmits arotation of the step motor 70 to a cam drive gear 74 via thetransmission mechanism (configured of a motor gear 71, firsttransmission wheel 72, and second transmission wheel 73).

The step motor 70 is held by a motor support frame 19, and fixed to thefirst machine casing 15 by fixing screws 93. The step motor 70 includesthe motor gear 71.

The first transmission wheel 72 and second transmission wheel 73 arerotatably journaled by the first machine casing 15 and second machinecasing 16.

The first transmission wheel 72 is journaled by a bearing 115 providedin the first machine casing 15, and a bearing 112 provided in the secondmachine casing 16, in a condition in which a transmission gear 72 a isjournaled on a pinion 72 b.

The second transmission wheel 73 is journaled by a bearing 113 providedin the first machine casing 15, and a bearing 113 provided in the secondmachine casing 16, in a condition in which a transmission gear 73 a isjournaled on a pinion 73 b.

Also, a cam drive gear 74, configuring a cam drive wheel 80 by, togetherwith the cam 20, being journaled on a cam shaft 75, is journaled by abearing 114 provided in the first machine casing 15, and a bearing 114provided in the second machine casing 16. Between the motor gear 71 andcam drive gear 74, as well as the gear ratio of each gear being set, apredetermined rotary speed and rotary torque of the cam 20 are set, insuch a way as to provide a deceleration drive.

The step motor 70, first transmission wheel 72, second transmissionwheel 73, and cam drive wheel 80 are disposed in the space 100configured by the first machine casing 15 and second machine casing 16.The bonding surfaces of the first machine casing 15 and second machinecasing 16 are closely bonded together.

As a first machine casing 15 and second machine casing 16 bondingstructure, it is possible to employ a structure in which they are fixedusing kinds of fixing screw 91 shown in FIG. 5, a structure in which thebonding surfaces thereof are welded or adhesively attached together, orthe like.

Also, the control circuit 30, being provided in the control unit 12, isconnected to the step motor 70 via a circuit pattern provided on anunshown circuit substrate, causing the step motor 70 to rotate at apredetermined rotary speed.

The cam 20 having concavities and convexities in an outercircumferential direction, finger pressing surfaces 21 a to 21 d areformed on the outermost periphery. The finger pressing surfaces 21 a to21 d are formed on a concentric circle equidistant from the rotationcenter P.

Also, the circumferential pitches and contours of the finger pressingsurface 21 a and finger pressing surface 21 b, the finger pressingsurface 21 b and finger pressing surface 21 c, the finger pressingsurface 21 c and finger pressing surface 21 d, and the finger pressingsurface 21 d and finger pressing surface 21 a, are formed equal to eachother.

Each of the finger pressing surfaces 21 a to 21 d is formed continuouswith a finger pressing slope 22 and an arc portion 23 on a concentriccircle having the rotation center P as its center. The arc portions 23are provided in positions in which they do not press the fingers 40 to46.

Also, the extremities of the finger pressing surfaces 21 a, 21 b, 21 c,and 21 d, and the arc portions 23, are connected by linear portions 24extended from the rotation center P.

Next, a description will be given, referring to FIGS. 5, 6A, and 6B, ofa configuration of the tube unit 11. The tube 50, one portion of whichfacing the cam 20 has the arc shape, is mounted in a tube guide groove17 c formed in the first tube guide frame 17.

The radius point P′ (refer to FIGS. 3A to 3C) of the arc shape of thetube 50 coincides with the rotation center P of the cam 20 in thecondition in which the tube unit 11 is mounted in the control unit 12.The one extremity of the tube 50 communicates with the reservoir 14, andthe other extremity is the flow outlet 53 extended through the tubeinsertion hole 13 a in the fixing frame 13.

The fingers 40 to 46 are inserted in the finger guide slots 85 formed bythe first tube guide frame 17 and second tube guide frame 18. The fingerguide slots 85, being provided corresponding one to each of the fingers40 to 46, are equally spaced and extended radially from the rotationcenter P of the cam 20 (that is, coinciding with the arc radius point P′of the tube 50).

As the fingers 40 to 46 are formed in the same shape, a description willbe given exemplifying with the finger 43.

As shown in FIG. 6B, the finger guide slot 85 is configured by sealingan opening on the upper side, as seen in the drawing, of anapproximately U-shaped groove 15 h formed in the first tube guide frame17, with the second tube guide frame 18. The finger guide slot 85penetrates from the tube guide groove 17 c to the wall surface 18 a.

As shown in FIG. 6A, the finger 43 is configured of a columnar shaft 43a, a flange shaped tube pressing portion 43 c provided at one extremityof the shaft 43 a, and a cam abutment portion 43 b obtained by roundingthe other extremity into a hemisphere.

The diameter of the tube pressing portion 43 c is set larger than thediameter of the finger guide slot 85, regulating an axial movement ofthe finger 43, preventing the finger 43 from falling off the tube unit11.

After the shaft 43 a of the finger 43 is mounted in the groove 15 h fromthe direction of the opening, the second tube guide frame 18 is mountedon the first tube guide frame 17 from above, thereby regulating aposition of the finger 43 in a sectional direction.

Nearly the whole of the tube 50 is mounted in the tube guide groove 17c, thereby regulating a plan position of the tube 50, and also, aprotrusion acting as a tube holding portion is formed in one portion ofthe side wall of the tube guide groove 17 c, thus restricting alevitation of the tube 50.

FIG. 7 is a fragmentary sectional view showing the tube holdingstructure. FIG. 7 illustrates it exemplifying with a protrusion betweenthe finger 45 and finger 46, from among protrusions between adjacentones of the fingers 40 to 46 (refer also to FIG. 5).

In the tube guide groove 17 c, a tube guide side wall 17 f, acting as aprotrusion with a width such as not to interfere with an advance andwithdrawal of the fingers 45 and 46, is provided between the finger 45and finger 46, and a kind of protrusion 17 e protruding over one upperportion of the tube 50 is formed in an upper portion of the tube guideside wall 17 f.

In this way, by the tube guide side wall 17 f and protrusion 17 e beingprovided between adjacent fingers, the tube position regulation in theplan direction and the suppression of the levitation of the tube arecarried out in a range in which the fingers 40 to 46 are disposed.

In the embodiment, as shown in FIG. 5, protrusions 17 h having the samefunction as the protrusions 17 e are provided in a position close to theflow outlet 53 of the tube, and in a position close to the flow inlet 52too.

In a condition in which the tube 50, reservoir 14, and fingers 40 to 46are mounted on the first tube guide frame 17, the first tube guide frame17 and second tube guide frame 18, the bonding surfaces thereof beingclosely bonded together, are fixed using fixing screws 92, therebyconfiguring the tube unit 11.

A space between the tube guide groove 17 c and tube 50, in the vicinityof the flow outlet 53 of the tube 50, is hermetically sealed using apacking, an adhesive, or the like, in a condition in which the firsttube guide frame 17 and second tube guide frame 18 are fixed. By sodoing, a hermetically sealed structure is established inside the tubeunit 11.

Also, the packing 97 being fitted over the outer periphery of the tubeunit 11 in the vicinity of the fixing frame 13, in the condition inwhich the tube unit 11 is inserted in the control unit 12, the interioris made a hermetically sealed space, providing the micropump 10 with awaterproof structure and a dust-proof structure.

In the event that it is sufficient that the micropump 10 is of anon-waterproof structure, the packing 97 is unnecessary.

Also, at least in a plan range of the tube guide groove 17 c in whichthe fingers 40 to 46 press the tube 50, a tube regulation wall 17 dformed by a recess extending along the tube guide groove 17 c is formedin a direction in which the fingers 40 to 46 advance.

An elastic member 60 is provided in the recess. That is, the elasticmember 60 is provided between the tube regulation wall 17 d and tube 50.The elastic member 60 is provided in such a way as to act as a damperwhen the tube 50 is pressed and closed with a pressure higher thannecessary by the fingers 40 to 46, preventing the tube 50 fromdeteriorating. The elastic member 60 has elasticity which withstands thepressure and closure of the tube. It is more preferable that thecoefficient of friction of the elastic member 60 with the tube 50 ismade low.

Also, an air vent filter 65 acting as a mutual communication member isprovided in a portion in which are bonded the flow inlet 52 of the tube50 and the reservoir 14. A lyophilic filter in which pores are formed isprovided inside the air vent filter 65. The filter allows the liquid topass therethrough, and blocks a passage of air bubbles.

In the embodiment, the air vent filter being made a member forconnecting the reservoir 14 and the tube 50, it is possible to carry outa separation and insertion of the tube 50 with respect to the reservoir14.

The pores formed in the filter are in a range of 0.1 μm to 1 μm,allowing the liquid to pass therethrough, and suppressing an intrusioninto the tube 50 of air bubbles equal to or more than 0.1 μm or 1 μmgenerated in the reservoir 14.

Protrusions 17 b are formed on side surfaces and rear surfaces in theproximal portion (on the fixing frame 13 side) of the first tube guideframe 17, and protrusions 17 n are formed on side surfaces and rearsurfaces at the leading extremity, while the same kinds of protrusion 18b and 18 e are formed on outer front surfaces in the proximal portion,and at the leading extremity, of the second tube guide frame 18 too.

In a condition in which the first tube guide frame 17 and second tubeguide frame 18 are bonded together, the protrusions 17 b and 18 b aremade continuous ring shaped protrusions, and the protrusions 17 n and 18e are made continuous ring shaped protrusions.

The tube unit 11 is slidingly inserted into the control unit 12. At thistime, the protrusions 17 b, 17 n, 18 b, and 18 e are provided, therebyincreasing a control unit 12 and tube unit 11 position accuracy, as wellas reducing a resistance at a time of insertion or removal.

A protrusion 96 with a groove 96 a is formed at the tail (on the fixingframe 13 side) of the tube unit 11. The protrusion 96 is used whenpinching the groove 96 a and removing the tube unit 11 from the controlunit 12.

Continuing, a description will be given, referring to FIG. 5, of anoperation relating to a transportation and discharge of the liquidaccording to the embodiment. In the condition shown in FIG. 5, the cam20 is rotated (in a direction of an arrow R in the drawing) via thetransmission mechanism by the torque from the step motor 70, and thefinger 44 is pressed by the finger pressing surface 21 d of the cam 20,pressing and closing the tube 50.

The finger 45 is also in abutment with a finger pressing surface 21 dand finger pressing slope 22 bonding portion, pressing and closing thetube 50. Also, the finger 46 is on the finger pressing slope 22, andpressing the tube 50, but has a smaller amount of pressure than thefinger 44, and is not completely pressing and closing the tube 50.

The fingers 41 to 43, being in the range of the arc portion 23 of thecam 20, are in an initial position in which they do not press. Thefinger 40 is in abutment with the finger pressing slope 22 of the cam 20but, in this position, is not yet pressing and closing the tube 50.

On the cam 20 being further rotated in the direction of the arrow R fromthis position, the fingers 45 and 46 are pressed in this order by thefinger pressing surface 21 d of the cam 20, pressing and closing thetube 50. The finger 44 is released from the finger pressing surface 21d, opening the tube 50. The liquid flows into a position of a liquidflow portion 51 of the tube 50 in which the pressure and closure of thefinger is released, or a position thereof in which the tube 50 is notyet pressed and closed.

On the cam 20 being further rotated by the step motor 70, the fingerpressing slope 22 presses the fingers 40, 41, 42, and 43 in this ordersequentially from the liquid inflow side to the outflow side, and eachof the fingers, when reaching the finger pressing surface 21 c, pressesand closes the tube 50.

By repeating this kind of operation, the liquid is caused to flow fromthe flow inlet 52 side toward the flow outlet 53 side, and dischargedfrom the flow outlet 53.

At this time, two of the fingers 40 to 46 abut against one of the fingerpressing surfaces of the cam 20 and, when the finger pressing surfacemoves to a position in which it presses a next finger, it presses one ofthe fingers 40 to 46. The condition in which two fingers are pressed,and the condition in which one finger is pressed, are repeated in thisway, thereby forming a condition in which at least one finger is alwayspressing and closing the tube 50. A structure of the micropump usingthis kind of motion of the fingers 40 to 46 is called a peristaliticdrive method.

Consequently, according to the embodiment, as the tube unit 11 isseparable from the control unit 12 including the cam 20 which pressesthe fingers 40 to 46 which press and close the tube 50, in a conditionin which the tube unit 11 is alone, the tube 50 is maintained in anopened condition. For this reason, it is possible to prevent a decreasein discharge accuracy accompanying a deterioration in resilience due toa continuous pressure and closure of the tube 50, and maintain a desireddischarge accuracy.

Also, it is conceivable that the resilience of the tube 50 deterioratesby repeating the pressure and closure, and opening, of the tube 50 for along time, in which kind of case a tube replacement is needed, but it ispossible to easily replace the tube 50 as the tube unit after a certaintime of use.

Also, as the cam 20, step motor 70, and transmission mechanism areconfigured as the control unit 12, when the tube unit 11 is mounted inthe control unit 12, it is not necessary that the kinds of pinion andgear in the previously described heretofore known technology areconnected in mesh, meaning that there is no damage in a meshing process.

Also, in the event that the tube unit 11 is mounted in the control unit12 in a direction parallel thereto, it is possible to place the fingers40 to 46 into a condition in which they can press the tube.Consequently, no connection mechanism being needed between the motormodule and pump module as in the heretofore known technology, it ispossible to simplify the structure, it is possible to improve anassembling property, and furthermore, it is possible to realize areduction in thickness.

Also, it is possible to make the tube unit 11 far lower in cost than thecontrol unit 11 including the cam 20, step motor 70, transmissionmechanism, and control circuit 30. Therein, in the event that the tubeunit 11 including the tube 50 making direct contact with a chemical orthe like is used once and thrown away, and the control unit 12 isrepeatedly used, it is possible to reduce a running cost.

Also, the inner diameter and outer diameter of the tube 50 can beconsidered to have a variation in dimension. The variation in dimensionthereof affects the discharge accuracy. Therein, by the tube 50 and thefingers 40 to 46 which have a length complying with the dimension of thetube 50 being made one set to form a tube unit, it is possible toimprove the discharge accuracy.

Also, as the tube unit 11 is mounted inside the space 110 provided inthe control unit 12, the first machine casing 15 and second machinecasing 16 configuring the control unit 12 have a casing function,eliminating a need for a casing for housing the tube unit 11 and controlunit 12, enabling the simplification in structure.

Also, as a structure is such that the tube unit 11 is inserted into thecontrol unit 12 in a direction parallel thereto, it is possible to makethe reduction in thickness in comparison with the kind of stackingstructure in the heretofore known technology.

Also, the micropump 10 of the embodiment is configured so that thefingers 40 to 46 are pressed by the rotation of the cam 20, pressing andclosing the tube 50. Consequently, it is necessary to cause the radiuspoint P′ of the arc shape of the tube 50 to coincide with the rotationcenter P of the cam.

Therein, when the tube unit 11 is mounted in the control unit 12, byproviding guide portions (the wall surface 18 a and wall surface 15 a)one in each of them, and bringing the guide portions into abutment witheach other, it is possible to cause the radius point P′ of the arc shapeof the tube 50 to approximately coincide with the rotation center P ofthe cam, and all of the fingers 40 to 46 can reliably carry out thepressure and closure of the tube without providing a dedicated positionregulation member.

In the embodiment, one or all of the first machine casing 15, secondmachine casing 16, first tube guide frame 17, and second tube guideframe 18, or one portion or the whole of the first machine casing 15,second machine casing 16, first tube guide frame 17, and second tubeguide frame 18, are formed of a transparent material.

By so doing, it is possible to observe the internal component parts oran engagement relationship and drive condition of each component part,and it is possible to detect whether the condition is normal, wherethere is a problem, or the like. It is sufficient that a range madetransparent is at least a range of a portion desired to be observed.

Also, in the event of configuring in such a way that it is possible toobserve from the direction of the upper portion, or the direction of thelower portion, of the reservoir 14, it is possible to observe the amountof liquid stored. It is more preferable to make the reservoir 14 atransparent container.

Also, by housing the reservoir 14 in the tube unit 11, it is possible toreplace the tube 50 before deterioration in the event that the tube unit11 including the tube 50 is replaced at a point at which the liquid inthe reservoir 14 has run out, meaning that it is possible to increasethe reliability of the micropump.

Also, a configuration is such that the air vent filter 65 is provided asa connection member between the reservoir 14 and tube 50, and thereservoir 14 and tube 50 are attachable to and detachable from oneanother. Consequently, by removing a reservoir 14 in which there islittle chemical, and connecting a reservoir 14 in which is stored achemical to the tube 50, it is possible to use the micropump for a longtime.

Also, by providing the air vent filter 65 between the reservoir 14 andtube 50, it is possible to block a passage of air bubbles included inthe liquid into the tube 50, and prevent the air bubbles from beinginjected into a living organism when discharging the liquid, which is achemical, into the living organism, increasing safety.

Also, the reservoir 14 includes the septum 95 acting as a port forcausing the liquid to flow thereinto, and sealing it therein. Byproviding the reservoir 14 with the septum 95, it is possible to easilycarry out the injection of the liquid into the reservoir 14 in thecondition in which the tube 50 is connected to the reservoir 14.

Furthermore, by disposing the septum 95 in such a way as to protrudeoutwardly of the first tube guide frame 17, and expose the flow inlet ofthe septum 95 to the outside of the fixing frame 13, it is possible toeasily carry out the injection of the liquid into the reservoir 14 inthe condition in which the tube unit 11 is alone, or in the condition inwhich the tube unit 11 is mounted in the control unit 12.

Furthermore, it is also possible to easily carry out an additionalinjection of the liquid in a condition in which the micropump 10 is inuse.

Embodiment 2

Continuing, a description will be given, referring to the drawings, ofEmbodiment 2. Embodiment 2 has a feature in that there is provided anelastic member which biases the tube unit 11 toward the control unit 12.Consequently, a description will be given centered on differences fromEmbodiment 1.

FIGS. 8A and 8B showing one portion of a micropump according toEmbodiment 2, FIG. 8A is a partial plan view, and FIG. 8B is a sectionalview showing the E-E section of FIG. 8A. In FIG. 8A, a leaf spring 99acting as the elastic member is provided between the tube unit 11 andfixing frame 13.

The leaf spring 99 is fixed to a concave, leaf spring fixing portion 13f provided on the tube unit 11 side of the fixing frame 13. The focalpoint of the leaf spring 99 is on a center line J, biasing the tube unit11 toward the rotation center P of the cam 20.

By this means, the wall surface 18 a of the tube unit 11 and the wallsurface 15 a of the control unit 12 are brought into abutment on thecenter line J.

The fixing of the leaf spring 99 is carried out using a fixing methodsuch as thermally welding a guide shaft 13 g protruded from the leafspring fixing portion 13 f of the fixing frame 13, as shown in FIG. 8B.As it is sufficient that the leaf spring 99 does not fall off in acondition in which the fixing frame 13 is fixed, the leaf spring 99 doesnot necessarily have to be fixed.

It is conceivable that, when the tube unit 11 is fixed to the controlunit 12 using the fixing frame 13, a horizontal (plan direction) spaceoccurs between the tube unit 11 and control unit 12 due to a variationin dimension of component parts such as the tube unit 11, control unit12, fixing unit 13, and the like, and the tube 50 will not be able to bepressed and closed by the fingers 40 to 46.

Therein, by biasing the tube unit 11 in the direction of the controlunit 12 by means of the leaf spring 99, it is possible to bring the wallsurfaces 15 a and 18 a into abutment with each other, and cause theradius point P′ of the arc shape of the tube 50 to coincide with therotation center P of the cam 20, enabling all of the fingers 40 to 46 toreliably press and close the tube 50.

Also, the biasing force of the leaf spring 99 is set in such a way as tobe greater than the pressure of the fingers 40 to 46 against the tube.

By so doing, when the fingers 40 to 46 press and close the tube 50, thetube unit 11 (that is, the tube 50) does not move in a direction awayfrom the fingers 40 to 46, meaning that it is possible to reliably pressand close the tube.

In the embodiment, the leaf spring 99 is exemplified as the elasticmember but, not being limited to the leaf spring, it is acceptable touse a coil spring, or a flat plate having elasticity in a direction ofthickness, and it is also acceptable to adopt a structure using aplurality thereof.

Embodiment 3

Continuing, a description will be given, referring to the drawings, of amicropump according to Embodiment 3. Embodiment 3 has a feature in thata power source is housed in the tube unit. Consequently, a descriptionwill be given centered on differences from Embodiment 1.

FIGS. 9A and 9B showing one portion of the micropump according toEmbodiment 3, FIG. 9A is a partial plan view, and FIG. 9B is a sectionalview showing the G-G section of FIG. 9A. In FIGS. 9A and 9B, a smallbutton type battery 120 (hereafter expressed simply as a battery 120)acting as the power source is housed inside the tube unit 11.

The battery 120, together with the reservoir 14, is mounted in a recessformed in the first tube guide frame 17, and the top thereof is sealedby the second tube guide frame 18. Herein, when the lower surface, asseen in FIG. 9B, of the battery 120 is taken to be a minus pole, and theupper surface and side surface are taken to be a plus pole, the lowersurface is connected to a minus terminal 121, and the side surface isconnected to a plus terminal 122.

The minus terminal 121 and plus terminal 122 are connected by unshownleads to connection terminals 123 and 124 implanted upright at anextremity of the first tube guide frame 17.

The connection terminals 123 and 124 are protruded from the first tubeguide frame 17, and extended as far as the interior of the control unit12. Connection terminals (not shown) electrically independentlyconnected to the connection terminals 123 and 124 are provided on thecontrol unit 12, and these connection terminals are connected to thecontrol circuit 30 (refer to FIG. 5).

In the condition in which the tube unit 11 is mounted in the controlunit 12, electric power is supplied to the control circuit 30 from thebattery 120, and the micropump 10 attains a drivable condition.

It is also acceptable to adopt a structure in which the battery 120 ishoused inside the tube unit 11, and the reservoir 14 is provided outsidethe tube unit.

When changing a chemical in use, or when replacing a used tube 50, byreplacing the battery 120 together with the tube 50 as the tube unit 11,it is possible to prevent a battery capacity from running short duringuse.

Also, the battery 120 is mountable in and removable from the tube unit11. The configuration shown in FIGS. 9A and 9B shows one example inwhich the fixing screws 92 (refer to FIG. 5) which join the first tubeguide frame 17 and second tube guide frame 18 together are removed, andthe battery 120 mounted and removed.

Herein, as a battery 120 mounting and removing structure, it isacceptable to adopt a structure in which a battery cap is provided inthe second tube guide frame 18, and it is also acceptable to adopt astructure in which, by establishing a structure in which the battery 120is slidingly inserted from the tail (the fixing frame 13 side) of thetube unit 11, the battery 120 is mounted and removed with the fixingframe 13 removed.

In this embodiment, the small button type battery is exemplified as thebattery, but it is possible to employ, apart from that, a secondarybattery such as a sheet battery or a lithium ion battery. In the eventof using these batteries, it is possible to dispose any one of them andthe reservoir superimposed one on the other, and there is an advantagein that it is also possible to increase the capacity of the reservoir inthe event of adopting a structure in which the battery is housed in thetube unit.

Embodiment 4

Continuing, a description will be given, referring to the drawings, of amicropump according to Embodiment 4. Embodiment 4 has a feature in thatthere is provided a detector, including a connection terminal anddetection terminal, which detects whether the tube unit is inserted inan accurate position in the control unit. Consequently, a descriptionwill be given centered on differences from Embodiment 1.

FIGS. 10A and 10B showing one portion of the micropump according toEmbodiment 4, FIG. 10A is a partial plan view, and FIG. 10B is asectional view showing the H-H section of FIG. 10A. In FIGS. 10A and10B, a first connection terminal 66 and second connection terminal 67are implanted upright at peninsular extremities on both sides of thewall surface 18 a formed in the tube unit 11.

One extremity of each of the first connection terminal 66 and secondconnection terminal 67 is electrically connected by a connection lead94. Also, the other extremities are protruded from control unit sideextremities 18 c and 18 d in such a way as to thrust into the interiorof the control unit 12.

An approximately U-shaped spring shaped first detection terminal 68 andsecond detection terminal 69 are provided on the control unit 12 (thefirst machine casing 15). As the first detection terminal 68 and seconddetection terminal 69 are of the same shape, a description will be givenexemplifying with the second detection terminal.

The second detection terminal 69 is mounted, bent, in a recess providedin the first machine casing 15. Herein, arms 69 a and 69 b of the seconddetection terminal 69 press opposed side walls in the recess.

Consequently, the arm 69 a is positionally regulated by a side wall 15 gin the recess. The position of the side wall 15 g is accuratelypositionally regulated in relation to the position of the rotationcenter P of the cam 20. Also, the positions of the leading extremitiesof the first connection terminal 66 and second connection terminal 67are also accurately positionally regulated in relation to the positionof the rotation center P of the cam 20.

When the tube unit 11 is mounted in the control unit 12 as far as aposition in which the arc shaped wall surface 18 a of the tube unit 11and the arc shaped wall surface 15 a of the control unit come intoabutment with each other, the second connection terminal 67 iselectrically connected to the second detection terminal 69. At the sametime, the first connection terminal 66 is also electrically connected tothe first detection terminal 68.

A lead 64 is connected to the second detection terminal 69, and the lead64 is connected to a detection terminal A (not shown) of the controlcircuit 30. Meanwhile, a lead 63 is connected to the first detectionterminal 68, and the lead 63 is connected to a detection terminal B (notshown) of the control circuit 30.

Herein, when it is detected by the detection terminal A and detectionterminal B that the second connection terminal 67 and second detectionterminal 69, and the first connection terminal 66 and first detectionterminal 68, have been electrically connected, it is determined that thewall surface 18 a of the tube unit 11 and the wall surface 15 a of thecontrol unit have come into abutment with each other.

When in this kind of condition, it is determined that the radius pointP′ of the arc shape of the tube 50 coincides with the rotation center Pof the cam 20, and the step motor 70 (not shown) is placed into adrivable condition by the control circuit 30.

Also, in the event that neither the second connection terminal 67 andsecond detection terminal 69, nor the first connection terminal 66 andfirst detection terminal 68, are electrically connected, it isdetermined that the tube unit 11 and control unit 12 are in a conditionin which they are not mounted in a predetermined position, and amounting of the tube unit 11 in the control unit 12 is done again.

In this embodiment, a contact type is exemplified as the detector, butit is possible to employ an optical detection or magnetic detectionstructure.

With this kind of configuration, by driving the step motor 70 in theevent of detecting that the radius point P′ of the arc shape of the tube50 and the rotation center P of the cam 20 have been caused to coincide,it is possible to press and close, and open, the tube 50 as it is set,meaning that it is possible to transport the liquid at a desired flowper unit time.

Embodiment 5

Continuing, a description will be given, referring to the drawings, of amicropump according to Embodiment 5. Embodiment 5 has a feature in thata battery acting as the power source is housed in the control unit.Consequently, a description will be given centered on differences fromEmbodiment 1.

FIGS. 11A and 11B showing one portion of the micropump according toEmbodiment 5, FIG. 11A is a plan view, and FIG. 11B is a sectional viewshowing the I-I section of FIG. 11A. In FIGS. 11A and 11B, a smallbutton type battery 120 (hereafter expressed simply as a battery 120)acting as the power source is housed in the control unit 12.

The battery 120 is mounted in a recess formed in the first machinecasing 15, and the top thereof is sealed and fixed by a battery cap 130.Herein, when the lower surface, as seen in FIG. 11B, of the battery 120is taken to be a minus pole, and the upper surface and side surface aretaken to be a plus pole, the lower surface is connected to a minusterminal 121, and the side surface is connected to a plus terminal 122.

The minus terminal 121 and plus terminal 122 are connected to powersource terminals (not shown) of the control circuit 30 by unshown leads.

The battery cap 130 includes a battery guide portion 131 protruded insuch a way as to surround the outer periphery of the battery 120, and aflange portion 134. Threads 132 are formed on the outer periphery of thebattery guide portion 131, and engaged with a threaded portion of thesecond machine casing 16, thereby fixing the battery 120.

A groove 133 is formed in the battery cap 130, and an opening andclosing of the battery cap 130 is carried out by inserting a coin or thelike in the groove, and rotating the battery cap 130.

When screwing the battery cap 130, the junction of the flange portion134 and second machine casing 16 is closely tightened. By using apacking as a seal material between the flange portion 134 and secondmachine casing 16, it is possible to further improve an airtightness.

As a battery cap 130 fixing structure, it is also acceptable to adopt astructure in which the battery cap 130 is pressed into the secondmachine casing 16. Also, it is also acceptable that the battery cap 130is of a bayonet structure. It is also acceptable to adopt a structure inwhich an opening is provided in a side surface of the first machinecasing 15 and second machine casing 16, and the battery 120 is insertedfrom the opening, and fixed by the same kind of fixing frame fixingstructure as that of the fixing frame 13.

By housing the battery 120 in the control unit 12 in this way, it ispossible to carry out a battery replacement in the condition in whichthe tube unit 11 is mounted in the control unit 12, or in a condition inwhich the control unit 12 is alone.

By housing the battery 120 in the control unit 12, it is possible tocarry out a connection of the control circuit 30 and battery withoutusing the kinds of connection terminal 123 and 124 in Embodiment 3(refer to FIGS. 9A and 9B), enabling the simplification in structure.

Also, by disposing the battery 120 in a space of the control unit 12outside a range in which the tube unit 11 is mounted, it is possible tomake the battery 120 thicker than with the structure in which thebattery 120 is mounted in the tube unit 11, meaning that it is possibleto employ a battery with a larger capacity.

Furthermore, as a vacant space increases in the tube unit 11, it ispossible to increase the liquid capacity of the reservoir 14 by thatamount.

As heretofore described, with each previously described micropump 10according to Embodiment 1 to Embodiment 5, the reduction in size andthickness is possible, enabling a minute amount of flow to flow stablyand continuously, meaning that, mounted inside, or on the surface of, aliving organism, it is suitable for a medical use such as a developmentof new drugs, a drug delivery, and the like. Also, in various kinds ofmechanical apparatus, it is possible to mount the micropump 10 inside oroutside the apparatus, and utilize it for transporting a fluid such aswater, a salt solution, a chemical, an oil, an aromatic solution, ink, agas, or the like. Furthermore, it is possible to utilize the micropumpalone for causing the liquid to flow, and supplying the liquid.

The entire disclosure of Japanese Patent Application No. 2008-249798,filed Sep. 29, 2008 is expressly incorporated by reference herein.

What is claimed is:
 1. A micropump comprising: a tube unit including atube and a plurality of fingers; a control unit including a cam and acontrol circuit, the tube unit being attachable to and detachable fromthe control unit; wherein the tube unit has a power source whichsupplies power to the control circuit, and the tube deforms via theplurality of fingers in accordance with the rotation of the cam drivenby the control circuit; and wherein a plurality of convexities areformed on the cam that form a plurality of finger pressing surfaces thatactuate the plurality of fingers; the convexities each being separatedby a planar surface that extends radially outward from a concentricsurface formed on a circle of the cam, and each convexity including afinger pressing surface that includes a finger pressing slope surfaceand a surface that is arc-shaped, the surface that is arc-shaped beingpart of the concentric surface and provided in a position that does notpress the fingers.
 2. The micropump according to claim 1, wherein thepower source is removably mounted to the tube unit.
 3. The micropumpaccording to claim 1, further comprising: a reservoir detachablyattached to the tube unit.
 4. The micropump according to claim 3,wherein the reservoir includes a re-sealable port for introducing fluidinto the reservoir.
 5. The micropump according to claim 1, furthercomprising: a reservoir housed in the tube unit.
 6. The micropumpaccording to claim 1, further comprising: a reservoir; wherein thereservoir and the power source are housed in the tube unit.
 7. Amicropump comprising: a tube unit including a tube and a plurality offingers; a control unit including a cam and a control circuit, the tubeunit being attachable to and detachable from the control unit; whereinthe tube unit has a power source removably mounted directly theretowhich supplies power to the control circuit; and wherein a plurality ofconvexities are formed on the cam that form a plurality of fingerpressing surfaces that actuate the plurality of fingers; the convexitiesare each separated by a planar surface that extends radially outwardfrom a concentric surface formed on a circle of the cam; and each fingerpressing surface includes a finger pressing slope surface and a surfacethat is arc-shaped, the surface that is arc-shaped being part of theconcentric surface and provided in a position that does not press thefingers.
 8. The micropump according to claim 7, further comprising areservoir detachably attached to the tube unit.
 9. The micropumpaccording to claim 8, wherein the reservoir includes a re-sealable portfor injecting a fluid thereinto.
 10. The micropump according to claim 7,further comprising a reservoir housed in the tube unit.